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Computer geek uncovers British climate-data errors

Paola Totaro

LONDON: The British Meteorological Office has been forced to correct its global temperature records after a science blogger discovered that Australian weather data had been misused or discarded.

The mistakes were discovered by Dr John Graham-Cumming when the temperature records were made public by the office in December in the wake of the East Anglia University email scandal.

Dr Graham-Cumming, a London mathematician and computer programmer who describes himself as a ''computer geek'', found that data from seven weather stations in Australia had been accidentally discarded while another 112 Australian stations - or 28 per cent of the Oceania total - had not been fully included in the calculations.

''What appears to have happened is that the Met Office calculated the averages and then got more data from Oceania and then failed to update the averages,'' Dr Graham-Cumming said.

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''The site with the greatest error was Napier Nelson Park, in New Zealand, where the average temperature was off by more than 1 degree. That's a lot given that the total warming seen since the 1970s is less than 1 degree and for this location the Met Office had it more than 1 degree hotter than it is. Had the error I'd found been more widespread, it could have had a real effect on the overall picture.''

He said that when the office checked his findings it discovered similar problems with US weather data, with 121 stations assigned to the wrong location or overwritten in the calculations.

Dr Graham-Cumming was at pains to point out that errors made by the office do not alter the big picture on climate change.

''It does not change the scientific story, and that is that the world is getting hotter,'' he said.

''But it does show the need for open-source data. We open up software and data and it eliminates problems.

''There are lots of people with a background in maths and programming. If you open it up, there will be many eyes cast across the data and you can find problems without having to go to expensive reviews.

''There are hundreds of enthusiastic amateurs who will have a go and do it non-politically.''

The land-based temperature records collected by the British Meteorological Office form a central plank of the scientific evidence for global warming.

The office has collated global temperature readings back to 1850, and while the raw data have not been freely available, graphs representing it have been.

The office provided details this week of its self-imposed review of global temperature records, announced last month, in an effort to try to regain public trust in climate science in the wake of the East Anglia University debacle.

In a document entitled ''Proposal for a New International Analysis of Land Surface Air Temperature Data'', the office argued that it was time to propose an international effort to reanalyse surface temperature data in collaboration with the World Meteorological Organisation.

The new analysis, which is expected to take three years, aims to test the conclusions reached by the United Nations Intergovernmental Panel on Climate Change that ''warming of the climate system is unequivocal''.

The Times reported that the World Meteorological Organisation said the Met Office proposal had been approved in principle by delegates at a meeting in Antalya, Turkey.